Identification of novel ondansetron metabolites using LC/MSn and NMR.

Ondansetron, a potent and highly sensitive 5-hydroxytryptamine type 3 (5-HT3) receptor antagonist, has been used for the treatment of chemotherapy- and radiotherapy-induced nausea and vomiting. The isolation and identification of ondansetron metabolites were investigated in our research. The feces and bile samples collected after oral administration of ondansetron were extracted and then isolated by semi-preparative HPLC. Then the pretreated samples were characterized by LC/MSn and NMR. In rats feces, a total of four metabolites were isolated and elucidated including 7-hydroxyl-ondansetron (M1), 8-hydroxyl-ondansetron (M2), 7-hydroxyl-N-desmethyl-ondansetron (M3), and 8-hydroxyl-N-desmethyl-ondansetron (M4). In addition, a kind of metabolite of phase II isolated in rats bile was characterized as N-desmethyl-ondansetron-7-O-ß-D-glucuronide (M5). To our knowledge, three metabolites were reported for the first time. LC/MSn and NMR-based approach was proved to be useful for full structure elucidation of unknown metabolites. The systematic metabolites isolation and elucidation provided metabolite reference standards for metabolites detection of ondansetron.

Chemical stability of ondansetron hydrochloride with other drugs in admixtures via parenteral; a review.

OBJECTIVE: This review was prepared to offer the most complete information about the use of ondansetron in parenteral admixtures with other drugs. METHOD: The search was done from September 2016 to April 2017 by using electronic databases Stabilis® and Micromedex® solutions, Medline/PubMed and Scholar Google searching publications about ondansetron stability in parenteral infusion when is administered by itself or with other medication. RESULTS: 49 studies are included with a total of 53 drugs. 15 drugs were found compatible administered with ondansetron in a clinical routine concentration range in intravenous administration. Also, four ternary blends were found compatible and another one was incompatible. Otherwise, 38 drugs were found incompatible. DISCUSSION: Compatibility of ondansetron offers a broad number of options to be used to avoid nausea and vomiting symptoms in patients with other concomitant medication.

Objetivo: Esta revisión ha sido preparada para recopilar toda la información referente a la estabilidad del ondansetrón en mezclas parenterales junto a otros fármacos.Método: La búsqueda fue realizada entre septiembre de 2016 y abril de 2017 empleando bases de datos electrónicas como Stabilis® y Micromedex® solutions, Medline/PubMed y Google Académico buscando publicaciones sobre la estabilidad del ondansetrón para infusión vía parenteral cuando es administrado en monoterapia o en una mezcla con otros fármacos.Resultados: En este trabajo han sido incluidos 49 artículos con un total de 53 fármacos. 15 fármacos han sido descritos como compatibles con ondansetrón en concentraciones habituales en la clínica práctica para administración intravenosa. Además, cuatro mezclas ternarias han sido descritas como compatibles y una como incompatible. Por otro lado, 38 fármacos han sido descritos como incompatibles para su administración con ondansetrón.Discusión: La compatibilidad del ondansetrón ofrece un amplio rango de opciones para evitar los síntomas de náuseas y vómitos en pacientes con otra medicación concomitante.

Long-term stability of dexamethasone and alizapride or ondansetron in sodium chloride 0.9% polyolefin bag at 5±3°C.

INTRODUCTION: The aim of the study was to investigate the long-term stability of dexamethasone 10mg associated with alizapride 100mg or ondansetron 8mg in 100mL of 0.9% sodium chloride solution stored at 5±3°C. METHOD: Solutions of 0.9% sodium chloride 100mL in polyolefin bags (n=5) containing approximately dexamethasone (DEX) 10mg associated with alizapride (ALI) 100mg or ondansetron (OND) 8mg were prepared under aseptic conditions and stored about 30 days at 5±3°C. ALI, DEX and OND concentrations were measured by high-performance liquid chromatography (HPLC). Optic density measurement at different wavelengths, pH measurement and optic microscope observations were performed periodically during the storage. A forced degradation test with HCL 5M and NaOH 5M before and after heating at 100°C was also performed. Solutions were considered stable if the 95% one-sided lower confidence limit of the concentration remains superior to 90% of the initial concentration or 95% of the initial concentration when any signs of physical instability exist as recently recommend. RESULTS: The calibration was linear over the following range from 20 to 1.25mg/100mL for DEX, from 200 to 12.5mg/100mL for ALI and from 20 to 1.25mg/100mL for OND with a calculated correlation coefficient (r2) of 0.998, 0.999 and 0.999, respectively. The inter- and intra-assay precision was below 10% for both mixtures. All formulations were physically stable during the storage. The lower confidence limit of the concentration for these solutions remains superior to 90% of the initial concentration at this date as recommended by the Food and Drug Administration (FDA) until 30 days. CONCLUSION: The HPLC method is specific and reproducible and can easily be adopted for monitoring the quality control in the production of DEX-ALI and DEX-OND bags. Solutions of DEX-ALI and DEX-OND were physically and chemically stable for 30 days in polyolefin bags stored at 5±3°C and could therefore be prepared in advance.

Multi-walled carbon nanotubes/Nafion composite film modified electrode as a sensor for simultaneous determination of ondansetron and morphine.

The electrochemical behavior of ondansetron was studied on the multi-walled carbon nanotubes/Nafion polymer composite modified glassy carbon electrode (MWCNTs-Nafion/GCE). The oxidation peak potential was shifted from 1.32 V to 1.18 V compared to the bare electrode indicating excellent electrocatalytic activity of immobilized film toward drug molecule. The modified electrode exhibited a remarkable enhancement effect on voltammetric response due to the synergistic effect of nanomaterial and cation-exchange polymer on the electron transfer rate, the effective electrode area and the accumulation capability. After optimizing the experimental parameters, adsorptive stripping procedure was used for the determination of ondansetron in pharmaceutical formulation. The results were satisfactory in comparison with those obtained by high-performance liquid chromatography. In addition, the MWCNTs-Nafion/GCE exhibited high selectivity in the voltammetric measurements of ondansetron and co-administrated drug morphine with potential difference of 430 mV. The response peak currents had linear relationship with drug concentration in the range of 1.0 × 10(-7)-5.0 × 10(-6)M and 1.0 × 10(-7)-4.0 × 10(-6)M with detection limits 3.1 × 10(-8) and 3.2 × 10(-8)M for ondansetron and morphine, respectively. The electrode was successfully applied for simultaneous electrochemical sensing of both drugs in human serum samples after selective accumulation at the electrode surface.

Complementarity of UV-PLS and HPLC for the simultaneous evaluation of antiemetic drugs.

This work was dedicated to the development of a simple and direct multivariate UV spectrophotometric method for the simultaneous determination of three antiemetic drugs (ondansetron, dexamethasone and aprepitant) in a new organogel formulation developed for their simultaneous transdermal administration. This method that does not require separation of the drugs and sophisticated instrument will permit to control quality of this new transdermal form both during the optimization step and for a further routine control of this preparation at the pharmacy department of the hospital. Hence, a partial least squares regression model using the spectral data record from 260 to 288 nm and 5 components, has firstly been validated thanks to the evaluation of the REP% (under 7.9%) and secondly using an accuracy profile approach (acceptance limit of ±10%). Thereby, the method allows the quantitation of the drugs in the ranges (5-15 mg L(-1)), (4-8 mg L(-1)) and (20-50 mg L(-1)) for ondansetron, dexamethasone and aprepitant, respectively. An HPLC/UV reference method has also been developed. Optimal separation (2.52

On-line focusing of 5-hydroxy-tryptamine type 3 receptor antagonists via the combination of field-enhanced sample injection and dynamic pH junction in capillary electrophoresis with amperometric detection.

In the present work, an on-line dual focusing technique based on field-enhance sample injection (FASI) and dynamic pH junction (DypH) was developed for the analysis of two 5-hydroxy-tryptamine type 3 receptor (5-HT3) antagonists ondansetron (Ond) and tropisetron (Tro) by capillary electrophoresis with amperometric detection (CE-AD) system. By preparing the sample in a lower conductivity (FASI condition) and lower pH value (DypH condition) matrix relative to the background electrolyte (BGE) solution, a simple and effective dual focusing approach, FASI-DypH was achieved. In this stacking mode, a large amount of analytes could be electrokinetically injected into the capillary and stacked at the boundary of the sample and the BGE zone as a result of deprotonation and decrease in the electric field. Effects of separation, detection and FASI-DypH focusing conditions were investigated in detail. Under the optimum conditions, good separation for Ond and Tro was achieved within 8min. In comparison with the conventional CE-AD analysis method, the present dual focusing technique enabled the enhancement factors in terms of peak heights to reach 357-fold and 345-fold for Ond and Tro, respectively. The limits of detection (LODs) (S/N=3) for Ond and Tro were 2nM and 5nM, respectively. The intraday and interday repeatabilities (RSDs) were less than 4.5% and 2.9% for peak height and migration time, respectively. The proposed method was successfully applied for the analysis of Ond and Tro in human urine sample.

High-performance liquid chromatographic method optimization for ondansetron assay in extemporaneous topical gel and in marketed products.

The compounding and evaluation of ondansetron hydrochloride dihydrate topical gel, 2.5% w/w, were conducted in this study. The gelling agent was Carbopol 940. Ethanol 70% in purified water was used to dissolve the drug and disperse the gelling agent. A gel was formed by adding drops of 0.1 N sodium hydroxide solution. To assay this gel, we developed a simple and reproducible stability--indicating high-performance liquid chromatographic method. This method was validated for specificity, accuracy, and precision. The compounded gel was assayed in triplicate, and the average recovery was 98.3%. Ondansetron marketed products were analyzed for comparison with the compounded formulation. Assay, accuracy, and precision data of the compounded topical gel were comparable to the marketed products.

A validated micellar electrokinetic chromatography method for the quantitation of dexamethasone, ondansetron and aprepitant, antiemetic drugs, in organogel.

A micellar electrokinetic chromatography (MEKC) method was developed for the determination of three anti-vomiting drugs (aprepitant, dexamethasone and ondansetron) in pharmaceutical formulations. The method was optimized using a central composite design (CCD). Four main factors (borate buffer concentration, pH, methanol content and sodium dodecyl sulfate concentration) were optimized in order to obtain best resolutions and peak efficiencies in a minimum runtime. The separation was performed in a fused-silica capillary. After optimization, the background electrolyte consisted of a borate buffer (62.5mM, pH 8.75) containing sodium dodecyl sulfate (77.5mM) and methanol (3.75%). Under these conditions, a complete separation of each antiemetic drug and its respective internal standards was achieved in 38min. The method was validated with trueness values from 94.9 to 107.2% and precision results (repeatability and intermediate precision) lower than 5.9%. MEKC-UV was the first method allowing the separation of aprepitant, dexamethasone and ondansetron and was suitable for the quantitation of these three antiemetic drugs in organogel formulations. The rapid sample preparation coupled with an automated separation technique make this method convenient for quality control of extemporaneous magistral ready-to-use formulation.

Development of HPTLC method for the estimation of ondansetron hydrochloride in bulk drug and sublingual tablets.

A new, simple, rapid, accurate and precise high performance thin layer chromatography (HPTLC) method has been developed for the estimation of ondansetron hydrochloride in bulk and sublingual tablets. The mobile phase composition was chloroform : ethyl acetate : methanol : ammonia (9:5:4:0.1 v/v). Spectrodensitometric analysis of ondansetron was carried out at 254 nm and a symmetrical, well-resolved, well-defined peak was obtained at mean retardation factor (R(f) ) 0.52 ± 0.02. The calibration plot was linear in the range 200-1200 ng/spot and showed good linear relationship with coefficient of regression, R(2) = 0.9952 with respect to peak area. The method was validated according to the guidelines of the International Conference on Harmonization (ICH Q2(R1). The limit of detection and quantitation were 14.83 and 44.92 ng per spot, respectively. The recovery study was carried out by standard addition method and the percentage recovery was found to be 99.34 ± 1.08. Therefore it was concluded that the proposed developed HPTLC method can be applied for identification and quantitative determination of ondansetron in bulk drug and dosage forms.

Formulation and in vivo evaluation of ondansetron orally disintegrating tablets using different superdisintegrants.

The aim of this study was to formulate cost effective taste-masked orally disintegrating tablets of ondansetron, a bitter drug using different superdisintegrants by a wet granulation technique. Microcrystalline cellulose (Avicel) as a diluent and disintegrant in addition to aspartame as a sweetener were used in all formulations. The prepared tablets were evaluated for weight variation, thickness, hardness, friability, drug content, water content, in vitro disintegration time and in vitro drug release. The tablets' hardness was maintained in the range of 2-3 kg and friability was <1% for all batches. All tablet formulations disintegrated rapidly in vitro within 5.83 to 33.0 sec. The optimized formulation containing 15% Polyplasdone XL-10 released more than 90% of drug within 5 min and the release was comparable to that of a commercial product. In human volunteers, optimized formulation was found to have a pleasant taste and mouth feel and they disintegrated in the oral cavity within 12 sec. The stability results were also satisfactory. A pharmacokinetic study with the optimized formulation was performed in comparison with a reference (Zofer MD 8®) and they were found to be bioequivalent. In conclusion, a cost effective ondansetron orally disintegrating tablet was successfully prepared with acceptable hardness, desirable taste and rapid disintegration in the oral cavity.

An electrochemical microfluidic platform for human P450 drug metabolism profiling.

This paper is the first report of a P450-electrode in a microfluidic format. A 30 µL microfluidic cell was made in poly(methyl methacrylate) containing the inlet, outlet, and reaction chamber with two electrode strips, one of which contains the human cytochrome P450 3A4 covalently bound to gold via a 6-hexanethiol and 7-mercaptoheptanoic acid (1:1) self-assembled monolayer. The electrochemical response of the P450-electrode in the microfluidic cell was tested using four drugs that are known substrates of P450 3A4: quinidine, nifedipine, alosetron and ondansetron. Titration experiments allowed the electrochemical measurements of K(M) for the four drugs, with values of 2.9, 29.1, 113.4, and 114.1 mM, respectively. The K(M) values are found to be in good agreement and correctly ranked with respect to the published literature on human liver microsomes and baculosomes: [ondansetron ≈ alosetron > nifedipine > quinidine]. The results presented in this paper represent a step forward for a rapid evaluation of the interaction of P450 and drug, requiring small volumes of new chemical entities to be tested.

Quantification of topotecan by liquid chromatography-mass spectrometry (LC-MS). Application to intestinal transport using rat everted gut sacs.

Topetecan is an important anti-cancer drug that has recently become available as an oral formulation. In order to study its intestinal absorption in vitro and a potential drug-drug interaction with the anti-emetic ondansetron, a sensitive and accurate method for the analysis of topotecan in biological media was required. We developed a liquid-liquid extraction method at pH 7.0-7.5 with a recovery of 85% and which took into account the complex chemical behaviour of topotecan related to the lactone opening and the keto-enol tautomerism. This enabled us to validate a new specific and sensitive LC-MS method of analysis, with satisfactory inter- and intra-day repeatability and accuracy. The method was applied to a study of topotecan uptake in rat everted gut sacs that showed that, despite being a P-glycoprotein substrate like topotecan, ondansetron did not interfere with topotecan uptake.

Determination of dexmedetomidine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a pharmacokinetic study.

A rapid, sensitive and selective high performance liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-ESI-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of dexmedetomidine (DMED) in human plasma. Dexmedetomidine and the internal standard (ondansetron) were extracted in a single step with diethyl-ether from 1.0 mL of alkalinized plasma. The mobile phase was a mixture of acetonitrile and 0.5% formic acid solution (30:70, v/v) at a flow rate of 0.2 mL min(-1). The detection was performed on a triple quadrupole tandem mass spectrometer in the selected reaction monitoring (SRM) mode using the respective [M+H]+ ions m/z 201.0-->95.1 for DMED and m/z 294.1-->170.1 for the IS. The assay exhibited a linear dynamic range of 5-5000 pg mL(-1) with the correlation coefficient above 0.9995. The lower limit of quantification (LLOQ) was 5 pg mL(-1) with a relative standard deviation of less than 15%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The validated HPLC-MS/MS method has been successfully applied to study the pharmacokinetics of three level doses of DMED in Chinese healthy volunteers.

Potential employment of non-silica-based stationary phases in pharmaceutical analysis.

The absolute majority of the HPLC applications use silica-based columns for the separation of active substance and its impurities. However, stationary phases based on metal oxides appear as an interesting alternative. The aim of our study was to investigate the potential utilization of metal oxide-based stationary phases in analytical evaluation of ondansetron and its five pharmacopoeial impurities. In our study commercially available ZrO(2)-based columns (e.g. Zr-PBD, Zr-PS, Zr-C18) and TiO(2)-based column were used. The effect of an organic modifier (type and ratio), a buffer (type, pH and concentration) and the influence of temperature was investigated. The separation of ondansetron and its five pharmacopoeial impurities was successfully accomplished on a Zirchrom-PBD column using a mobile phase consisting of acetonitrile-ammonium phosphate (25 mM, pH 7.0) (18:82, v/v). Detection was performed at 216 nm and the analysis was completed within 7.5 min. The paper proves metal oxide-based stationary phases as an alternative to classical silica-based stationary phases in pharmaceutical analysis.

Preparación de comprimidos de desintegración rápida de clorhidrato de ondansetrón mediante el método de compresión directa / Preparation of rapidly disintegrating tablets of ondansetron hydrochloride by direct compression method

Para elaborar comprimidos de desintegración rápida con un contenido de 8 mg de clorhidrato de ondansetrón, con sufi ciente integridad mecánica y buen sabor, se preparó una formulación de celulosa microcristalina (CM), lactosa anhidra, manitol y croscarmelosa. Los comprimidos se elaboraron mediante el método de compresión directa. Se determinaron propiedades tales como la resistencia a la fractura, el tiempo de desintegración, el tiempo de humidifi cación y la friabilidad. Para la preparación de los primeros lotes se utilizó el diseño experimental de compuesto de segundo orden esférico de dos factores, y para su optimización se empleó la función de deseabilidad. Para la preparación de los comprimidos de desintegración rápida se utilizó un diseño en retículos simple con restricciones en la proporción de los excipientes. En un diseño posterior, se seleccionaron como variables independientes la resistencia a la fractura y la concentración de celulosa microcristalina, de lactosa anhidra y de manitol. Para relacionar las variables independientes con la resistencia a la fractura y el tiempo de desintegración, se utilizaron ecuaciones matemáticas y representaciones gráfi cas. Además, para optimizar la formulación, se calculó el índice sintético que considera una desviación positiva o negativa a partir de un valor ideal. Se superpusieron las representaciones gráfi cas de la resistencia a la fractura y el tiempo de desintegración para encontrar la región optimizada en la que se pueden producir comprimidos con resistencia al aplastamiento y tiempos de desintegración aceptables. Para demostrar la similitud de la disolución en agua destilada y saliva simulada (pH 6,8) se utilizó el concepto de los factores de similitud f2 y Sd. Se podrían preparar comprimidos de desintegración rápida con una estructura duradera y un sabor agradable si se selecciona el nivel adecuado de CM, lactosa anhidra, manitol, croscarmelosa y fuerza de compresión

To make rapidly disintegrating tablets containing 8 mg ondansetron hydrochloride with suffi cient mechanical integrity as well as a pleasant taste, microcrystalline cellulose (MCC), lactose anhydrous, mannitol and croscarmellose were formulated. Tablets were prepared by a direct compression method. Tablets properties such as tensile strength, disintegration time, wetting time and friability were determined. The two-factor spherical second order composite experimental design was used for the preparation of preliminary batches and the desirability function was employed for the optimization of preliminary batches. For preparation of the rapidly disintegrating tablets, simplex lattice design with constraints on the proportion of excipients was utilized. In later design, tensile strength and disintegration time were selected as dependent variables and concentration of microcrystalline cellulose, concentration of lactose anhydrous and concentration of mannitol were selected as controlling factors. Mathematical equations and contour plots were used to relate independent variables with tensile strength and disintegration time. Furthermore, the composite index which considers a positive or negative deviation from an ideal value was calculated for the optimization of the formulation. Contour plots of tensile strength and disintegration time were superimposed to fi nd out the optimized region at which tablets with an acceptable crushing strength and disintegration time can be produced. The concept of similarity factors f2 and Sd were used to prove similarity of dissolution in distilled water and simulated saliva (pH 6.8). Rapidly disintegrating tablets with durable structure and desirable taste could be prepared by selecting proper level of MCC, lactose anhydrous, mannitol, croscarmellose and compression force

Microdialysis sampling coupled to HPLC for transdermal delivery study of ondansetron hydrochloride in rats.

The transdermal delivery of ondansetron hydrochloride (ON) solution in propylene glycol (PG) with a widely used penetration enhancer, oleic acid (OA), was studied in rats by a microdialysis sampling technique. Dialysate samples collected from the probe were directly injected into the HPLC system without any pre-treatment and no interference occurred in the blank sample. A good linearity between the standard concentrations and peak areas within the calibration range was achieved. In vivo recovery (32.52 +/- 1.8%) of the probe was assessed with the retrodialysis method, which was used to calculate the ON concentration in the dermis. Oleic acid at the concentrations of 2% and 5% (w/v) increased the steady-state delivery rate from 0.001 to 0.030 and 0.058 microg/h, respectively. OA proved to be an effective enhancer for transdermal delivery of ON in rats.

Enzyme-linked immunosorbent assay for ondansetron captured from airborne samples.

A simple and relatively rapid enzyme-linked immunosorbant assay method for the anti-emetic drug ondansetron has been developed for its quantitation in solution. This has been optimised for use with samples that have been obtained following extraction of filters after the drug's capture from air samples in the workplace. The assay has the sample throughput (40 duplicate samples in 3 h), specificity, sensitivity (LOD of 10.5 ng drug ml-1) and precision (RSD < 11%) necessary for its use in determining airborne concentrations of ondansetron in such samples as part of an occupational health and hygiene monitoring programme.

[Determination of Ondansetron in injection by high performance capillary zone electrophoresis].

Ondansetron is a kind of drug which is used for the treatment of nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy. In this paper, a method to determine Ondansetron in injection by high performance capillary zone electrophoresis is discussed. The injection was directly introduced into the capillary employing 40 mmol/L phosphate at pH 4.03 as buffer. The capillary used was 75 microns in i.d. and 47 cm in length. UV detection was set at 254 nm. The calibration curve showed good linearity. The recovery of Ondansetron ranged from 95%-98% with a coefficient of variation of 1.05%(n = 4). This method is simple, rapid and reliable.